Eugene S Enderson

US Patent:

44146892, Nov 8, 1983

Filed:

Dec 27, 1982

Appl. No.:

6/453647

Inventors:

Eugene S. Enderson - Robins IA

Assignee:

Rockwell International Corporation - El Segundo CA

International Classification:

H04B 110

US Classification:

455221

Abstract:

A squelch circuit for a radio receiver provides for applying the audio signal that has been detected and demodulated to both a low pass channel and high pass channel. The low pass channel passes the audio signal to a low frequency bandpass filter where only the lower frequencies of the demodulated signal are passed. The filtered signal is then average by an averaging detector where the average of the energy contained within the signal is obtained and monitored by a syllabic detector, which upon the occurrence of certain pre-established varying energy levels will indicate the presence of speech in the demodulated signal. The high pass channel includes a high frequency bandpass filter for passing signals with a frequency that is greater than the frequencies of those signals passed by the low frequency bandpass filter, a peak detector for detecting the concentration of signal energy and a level comparator for comparing the output of the averaging detector with the peak detector and to provide a positive indication when the average level is greater than the peak level. The output from the high pass channel and the low pass channel are ANDed together to provide a signal that will operate an audio gate for passing the demodulated signal on to the output means, when the output from the high pass channel, and the output from the low pass channel are ANDed together and provide a positive indication.

US Patent:

50602993, Oct 22, 1991

Filed:

Sep 29, 1989

Appl. No.:

7/414894

Inventors:

Eugene S. Enderson - Robins IA

Assignee:

Rockwell International Corporation - El Segundo CA

International Classification:

H04B 126

US Classification:

455326

Abstract:

A diode mixer characterized by low levels of intermodulation distortion. The mixer circuit includes a center-tapped input transformer for coupling the circuit to local oscillator and radio frequency signal sources and a center-tapped output transformer for coupling the circuit to an intermediate frequency load. The circuit also includes an arrangement of transformers and switching diodes for interfacing the input transformer to the output transformer and applying the local signals and radio frequency signals to the secondary output transformer in a special manner while favorably back-biasing diodes which are in the off condition for more rapid switching action.